<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 200px;
            height: 200px;
            margin: 0 auto;
        }
        .div1{
            margin-top: 100px;
            position: relative;
            border:1px solid #000000;
            transform:perspective(500px) rotateY(0deg);
            transform-style:preserve-3d;
        }
        .div1 div{
            position: absolute;
            top: 0;
            left: 0;
            font-size: 80px;
            line-height: 200px;
            text-align: center;
            background-color: #ff0000;
            transform:rotateY(45deg);
        }
    </style>
</head>
<body>
<div class="div1">
    <div class="div1_1">1</div>
</div>
</body>

</html>